1. Field of the Invention
The present invention is generally related to the field of semiconductor manufacturing and, more particularly, to various control methodologies using optical emission spectroscopy derived data, and a system for performing same.
2. Description of the Related Art
There is a constant drive within the semiconductor industry to increase the quality, reliability and throughput of integrated circuit devices, e.g., microprocessors, memory devices, and the like. This drive is fueled by consumer demands for higher quality computers and electronic devices that operate more reliably. These demands have resulted in a continual improvement in the manufacture of semiconductor devices, e.g., transistors, as well as in the manufacture of integrated circuit devices incorporating such transistors. Additionally, reducing the defects in the manufacture of the components of a typical transistor also lowers the overall cost per transistor as well as the cost of integrated circuit devices incorporating such transistors.
As device dimensions have continued to decrease, the ability to precisely form very small features to their desired dimension has become more important. Variations in the physical dimensions of such features can adversely impact device performance and reduce product yields. For example, the critical dimension and profile of gate electrode structures of transistors is one area where a very high degree of precision is desired. Absent precise control, adverse consequences may follow. For example, if the critical dimension of the gate electrode is greater than the target or design critical dimension, the transistor may not operate as fast as desired by the product design requirements. Conversely, if the critical dimension of the gate electrode structure is less than the target value, off-state leakage currents may be higher than desired. This situation is particularly problematic for integrated circuit devices intended for mobile telecommunication applications and those intended for mobile computing devices.
Etching processes are frequently employed in semiconductor manufacturing to define a variety of different types of features, such as gate electrode structures, conductive metal lines, openings in insulating layers, trenches in a semiconducting substrate, sidewall spacers, etc. Such etching processes, be they anisotropic or isotropic in nature, are very complex processes that involve a vast variety of interrelated variables, such as gas flow rates, temperature, pressure, power, and the characteristics of the plasma generated in some of the processes. Such complexities make it difficult to control etching processes such that the resulting features exhibit the desired physical dimensions and/or profile.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
The present invention is generally directed to various control methodologies using optical emission spectroscopy derived data, and a system for performing same. In one illustrative embodiment, the method comprises performing an etching process within an etch tool to define at least one feature above a semiconducting substrate, obtaining optical emission spectroscopy data for the etching process, and controlling at least one parameter of the etching process based upon a comparison of the obtained optical emission spectroscopy data and target optical emission spectroscopy data associated with at least one of a target profile and a target critical dimension for the at least one feature. In further embodiments, the controller acts to control one or more parameters of the etching process such that a metric for the obtained optical spectroscopy data is maintained within a preselected range of a metric for the target optical emission spectroscopy data. In even further embodiments, the metric for the obtained optical spectroscopy data is maintained below a preselected level or limit of a metric for the target optical emission spectroscopy data.
In one illustrative embodiment, the system is comprised of an etch tool adapted to perform an etch process to define at least one feature, an optical emission spectroscopy sensor operatively coupled to the etch tool, and a controller for controlling at least one parameter of the etching process performed in the etch tool based upon a comparison between optical emission spectroscopy data obtained from the optical emission spectroscopy sensor and target optical emission spectroscopy data associated with at least one of a target profile and a target critical dimension for the at least one feature. In further embodiments, the controller acts to control one or more parameters of the etching process such that a metric for the obtained optical spectroscopy data is maintained within a preselected range of a metric for the target optical emission spectroscopy data. In even further embodiments, the metric for the obtained optical spectroscopy data is maintained below a preselected level or limit of a metric for the target optical emission spectroscopy data.